<?php

    namespace wx;
    use yaliSDK\db\RedisDB;

    class JSSDK {
        private $appId;
        private $appSecret;
        private $db;
        public function __construct($appId, $appSecret) {
            $this->appId = $appId;
            $this->appSecret = $appSecret;
            $this->db = new RedisDB(config('redis'));
        }

        public function getSignPackage($url) {
            $jsapiTicket = $this->getJsApiTicket();

            // 注意 URL 一定要动态获取，不能 hardcode.
//            $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
//            $url = "https://tramp.o2osystems.com/index_share.html";
            $timestamp = time();
            $nonceStr = $this->createNonceStr();

            // 这里参数的顺序要按照 key 值 ASCII 码升序排序
            $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";

            $signature = sha1($string);

            $signPackage = array(
                "appId" => $this->appId,
                "nonceStr" => $nonceStr,
                "timestamp" => $timestamp,
                "url" => $url,
                "signature" => $signature,
                "rawString" => $string
            );
            return $signPackage;
        }

        private function createNonceStr($length = 16) {
            $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            $str = "";
            for ($i = 0; $i < $length; $i++) {
                $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
            }
            return $str;
        }

        private function getJsApiTicket() {
            // jsapi_ticket 应该全局存储与更新，以下代码以写入到文件中做示例

            $data = json_decode($this->db->get('WX_JSDK_jsapi_ticket'));
            if (!$data) { $data = ['expire_time'=>0]; }
            if ($data['expire_time'] < time()) {
                $accessToken = $this->getAccessToken();
                // 如果是企业号用以下 URL 获取 ticket
                // $url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi_ticket?access_token=$accessToken";
                $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";
                $res = json_decode($this->httpGet($url));
                $ticket = $res->ticket;
                if ($ticket) {
                    $data['expire_time']= time() + 7000;
                    $data['jsapi_ticket'] = $ticket;
                    $this->db->set($this->db->get('WX_JSDK_jsapi_ticket'), json_encode($data));
                }
            } else {
                $ticket = $data['jsapi_ticket'];
            }

            return $ticket;
        }

        private function getAccessToken() {
            // access_token 应该全局存储与更新，以下代码以写入到文件中做示例
            $data = json_decode($this->db->get('WX_JSDK_access_token'));
            if (!$data) { $data = ['expire_time'=>0]; }
            if ($data['expire_time'] < time()) {
                // 如果是企业号用以下URL获取access_token
                // $url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=$this->appId&corpsecret=$this->appSecret";
                $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";
                $res = json_decode($this->httpGet($url));
                $access_token = $res->access_token;
                if ($access_token) {
                    $data['expire_time'] = time() + 7000;
                    $data['access_token'] = $access_token;
                    $this->db->set($this->db->get('WX_JSDK_access_token'), json_encode($data));
                }
            } else {
                $access_token = $data['access_token'];
            }
            return $access_token;
        }

        private function httpGet($url) {
            $curl = curl_init();
            curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($curl, CURLOPT_TIMEOUT, 500);
            // 为保证第三方服务器与微信服务器之间数据传输的安全性，所有微信接口采用https方式调用，必须使用下面2行代码打开ssl安全校验。
            // 如果在部署过程中代码在此处验证失败，请到 http://curl.haxx.se/ca/cacert.pem 下载新的证书判别文件。
            curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, true);
            curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, 2);//
            curl_setopt($curl, CURLOPT_URL, $url);

            $res = curl_exec($curl);
            curl_close($curl);

            return $res;
        }

        private function get_php_file($filename) {
            return trim(substr(file_get_contents($filename), 15));
        }

        private function set_php_file($filename, $content) {
            $fp = fopen($filename, "w");
            fwrite($fp, "<?php exit();?>" . $content);
            fclose($fp);
        }
    }

